Abstract Kaufman: Air pollution, heart failure, and atrial fibrillation burden in MESA This proposal examines the impact of ambient air pollutants on the development, burden, and triggering of heart failure and atrial fibrillation. Air pollutants, especially particulate matter, have been associated with the incidence of cardiovascular disease, especially coronary heart disease and stroke. The incidence of coronary heart disease and stroke is declining due to prevention efforts, while development of heart failure (HF, especially with preserved ejection fraction, HFpEF) and atrial arrhythmias (especially atrial fibrillation, AF) are becoming more important components of the burden of cardiovascular disease; the role of environmental factors in these two frequently co-existing conditions diseases is largely unstudied. The Multi-Ethnic Study of Atherosclerosis (MESA) is an extraordinarily valuable cohort for understanding predictors and correlates of heart failure and atrial fibrillation, due to participants? ages, extensive existing phenotyping, and planned assessment in an examination beginning in 2016. In addition, MESA has become the most carefully studied cohort in terms of exposure to ambient air pollutants. This proposed study will extend the air pollutant characterization using innovative low-cost indoor and outdoor home-based monitoring and state-of-the-art modeling approaches incorporating extensive geographic inputs. We will characterize both the relationship between long-term ambient exposures to fine particulate matter (PM2.5), oxides of nitrogen (NOX), nitrogen dioxide (NO2), ozone (O3), and carbon monoxide (CO), and development of early stage heart failure and atrial arrhythmias, and the relationship between short-term exposure to air pollutants and triggering of atrial arrhythmias and AF burden. It is important to understand these relationships since: 1) Air pollutants are associated with cardiovascular mortality; 2) HF and structural disease correlates of HF are risk factors for AF; and 3) HFpEF with AF represents a group at especially high mortality risk. We will estimate long-term (annual average) and short-term (hourly and daily) concentrations of PM2.5, NOX, NO2, O3, and CO, outside and inside all MESA participants? homes using state-of-the-art monitoring technology and spatiotemporal statistical models. We will use novel low-cost pollutant monitoring sensors at a subset of MESA participant homes and community locations. Early evidence of prevalent HF subtypes and newly emerging sub-phenotypes will be assessed using information from in-exam echocardiographic cardiac parameters, 6-minute walk test results, arterial tonometry, and biomarkers (NTproBNP, sST2, galectin-3). Ambulatory novel two-week ECG monitoring and interrogations of implanted pacemakers and cardioverter-defibrillators will allow us to assess the association between long-term air pollution exposure and AF and short-term air pollution and the triggering of atrial arrhythmias. Through this effort, we will gain unprecedented insight into the role of air pollutants in development of cardiovascular disease, with a focus on HF, especially HFpEF, and on AF.